The present invention relates to a deformation element for a motor vehicle having a crossmember holder for mounting on a crossmember and having a bumper plate which can be positioned adjacent to a bumper of a motor vehicle. Moreover, the present invention relates to a motor vehicle equipped with such a deformation element.
For the purpose of protecting a motor vehicle in the event of a frontal accident, for protecting occupants of the motor vehicle involved in such an accident and also for protecting persons, in particular pedestrians, situated outside the motor vehicle and caught up in such an accident, a series of measures is provided.
In the case of a so-called low-speed crash, in which a comparatively high load of up to about 100 kN acts with a comparatively low speed of from 4 km/h up to about 20 km/h on the front region of a motor vehicle (for example, a crash when the vehicle bangs into an object while parking), a deformation element belonging to the vehicle is provided so that the load is taken up reversibly and in as disturbance-free a manner as possible.
To illustrate a pedestrian protection function in the front region of a motor vehicle, it is provided that a comparatively low load of up to about 5 kN in a comparatively high speed range from about 20 km/h to 40 km/h is taken up by a deformation element provided in the front region of the motor vehicle.
To realize protection in the case of a low-speed crash and for a pedestrian protection function, DE 10 2011 009 943 A1 discloses an energy-absorption system for installation between a bumper and a crossmember of a motor vehicle. In this system, a soft component and a hard component are inter-engaged and extend over the entire width of the motor vehicle. Using the known energy-absorption system can result in a comparatively large overhang (this is the distance from the wheel center point to the foremost point of the front cladding), which is not always desired from an aesthetic point of view and, additionally, negatively influences the ramp angle of the corresponding motor vehicle.
It is an object of the present invention to overcome the disadvantages of the prior art.
This and other objects are achieved by a deformation element having a crossmember holder for mounting on a crossmember and a bumper plate which can be positioned adjacent to a bumper of a motor vehicle. Furthermore, a friction device between the bumper plate and crossmember holder is provided for adjusting and fixing the distance from the crossmember holder to the bumper plate, wherein a first distance from the bumper to the crossmember holder—starting from a normal position i.e., meaning representing an accident-free situation—is greater in a first position different from the normal position than a distance in a second position different from the normal position. Here, the first position is assumed by the deformation element during the occurrence of a low-speed crash. The second position is assumed by the deformation element within the context of the pedestrian protection function. The distance from the bumper plate to the crossmember holder in the normal position is greater than the distance between said elements in the first position and the second position.
An advantageous configuration of the friction device makes possible a particularly precise and reliable function of the deformation element provided according to the invention. For this reason, it is provided that the friction device has a first friction surface between the crossmember holder and bumper plate and also a second friction surface between the crossmember holder and bumper plate such that the first friction surface allows adjustment and fixing of the bumper plate in the first position and blocks it in the second position, whereas the second friction surface allows adjustment and fixing of the bumper plate in the second position and blocks it in the first position.
The precision of the deformation element according to the invention is further improved if the friction device is a friction body, such as a wedge, on whose outer surface is at least partially situated the first friction surface interacting with the crossmember holder and on whose inner surface is at least partially situated the second friction surface interacting with the bumper plate.
For the purpose of easy producibility of the deformation element according to the invention and more precise guidance of the friction device, the bumper plate is situated on a plunger whose outer surface has a third friction surface which interacts with the second friction surface.
Provision can advantageously be made in the case of the deformation element according to the invention for the crossmember holder to be mounted on a sleeve which at least partially has on its inner side a fourth friction surface and which interacts with the first friction surface; the accuracy of the guidance of the friction device is further improved as a result.
For adequate, load case-dependent setting of the deformation element according to the invention, the coefficients of static friction and/or coefficients of sliding friction thereof can be freely selected in the region of each individual friction surface, a plurality of friction surfaces or all friction surfaces.
The aforementioned object is also achieved by a motor vehicle having a crossmember and a bumper, wherein a deformation element of the above-described type according to the invention is provided. The aforementioned advantages apply correspondingly.
According to the invention, a number of deformation elements according to the invention can be provided along the vehicle transverse direction, with the result that a whole series of load cases or protection functions is realized. Here, their position, for example their arrangement parallel to the vehicle vertical axis, can, in principle, be freely configured with respect to a vehicle body and is limited only by the underlying load case.
In a particularly advantageous manner, the deformation elements fastened in such a manner, in particular along the crossmember, have at least in part friction devices with different coefficients of friction. This makes it possible for the deformation elements to be adapted in a position-dependent manner to different load cases in a simple manner.
The above-described features of the present invention can, where possible, be combined with one another, even when not explicitly described above.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.